A submarine is emitting a sound wave underwater. The sound wave has a frequency of 500 Hz and a wavelength of 3 meters. The sound wave the submarine emits reflects off a ship and returns to the submarine. If it takes the sound wave 5 seconds to return to the submarine how far away is the ship?

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.

Carbon 14 is a naturally occurring stable

Debris produced by mining is called